1. Field of the Invention
The present invention relates to methods of combating production problems in wells containing defective gravel packs, and more particularly, to such methods whereby the defective gravel packs are inexpensively bypassed.
2. Description of the Prior Art
In completing oil, gas and water wells, a string of casing is often run into the well bore and cemented therein. A string of production tubing is run in the casing, and the well is perforated in one or more production zones to allow formation fluids to enter the casing. Formation fluids that flow through the perforations into the interior of the casing are produced to the surface through the production tubing.
During the production of fluids from a poorly consolidated formation, sand from the formation is often also produced which is carried with the fluids into the well and into production equipment. The presence of sand in the produced fluids causes erosion and other damage to the tubular goods and equipment through which the fluids flow.
In order to eliminate or reduce the production of formation sand, gravel packs have commonly been utilized heretofore. That is, a sand screen is placed in a well bore penetrating a poorly consolidated formation adjacent to the perforations through which formation fluids are produced. A packer is typically set above the sand screen and the annulus around the screen is then packed with a relatively coarse sand, commonly referred to as gravel. The gravel pack which is formed around the sand screen as well as in the perforations filters sand out of the in-flowing formation fluids.
While such gravel packs have been utilized extensively, they often develop defects which in turn cause production problems. For example, even when a gravel pack is consolidated by a hardenable resin composition, it can break down and allow the production of some sand with the formation fluids. The production of the sand eventually causes the sand screen to cut out whereby greater amounts of sand are produced. In other circumstances, the gravel pack may become plugged or partially plugged with debris from previously utilized stimulation or completion fluids whereby formation fluid production is materially decreased.
When a gravel pack becomes defective, its replacement has heretofore been difficult and expensive. Thus, there is a need for improved methods of combating production problems in wells containing defective gravel packs which are relatively simple and economical to carry out.